1. Field of the Invention
The present invention relates to a weather strip with built-in core to be attached to a flange formed on a frame defining an opening in the body of an automobile, a method of partially breaking the core of a weather strip, and a core breaking machine for partially breaking the core of a weather strip.
2. Description of the Related Art
Conventional cores to be buried in weather strips to be put on a flange formed on a frame defining an opening in the body of an automobile are classified into the following types:
a) Cores of a wire carrier type formed by bending a wire in the shape of a hairpin;
b) Cores of a breakout type formed by arranging U-shaped loops at intervals in the shape of a channel;
c) Cores of a rhombus type formed by punching a strip in a shape having a successive arrangement of rhombuses;
d) Cores of a lath type formed by punching holes in a strip;
e) Cores of fish-bone type formed by punching and bending a strip in a fish-bone shape.
A weather strip provided with the core of a breakout type is bendable, stretchable and contractible when putting the weather strip on the flange because the U-shaped loops are separated from each other and, therefore, the weather strip can be easily put on the flange. On the other hand, a weather strip provided with a core of a type other than the breakout type is bendable but neither stretchable nor contractible and, therefore, it is difficult to put the weather strip on the flange. However, the weather strip provided with a core of a breakout type is inferior in capability of holding to the flange and the weather strip is liable to fall off the flange.
Referring to FIGS. 1 to 4, a method of putting a weather strip 10 integrally provided with a core 20 of, for example, a fish-bone type formed by successively connecting U-shaped loops 21 by a longitudinal connecting part 22 as shown in FIG. 3 on a flange formed in a frame defining an opening in the body of an automobile, punches out a portion 23 of the connecting part 22 to enable the weather strip 10 to be stretched or contracted so that the length of the weather strip 10 coincides with that of the flange. Another method of putting the weather strip 10 on the flange forms the weather strip 10 in a length shorter than that of the flange, puts the weather strip 10 on the flange so that the opposite ends of the weather strip 10 are spaced apart, and an end cap 60 is put on and attached with an adhesive 70 to the opposite ends of the weather strip 10 as shown in FIG. 4. These methods require troublesome work.
The weather strip integrally provided with a core of a breakout type is formed by extruding rubber or synthetic resin in the shape of the weather strip together with a core, and bending the weather strip by a bender to break apart the U-shaped loops of the core so that the weather strip is stretchable and contractible to facilitate the work for putting the weather strip on the flange. However, this weather strip is liable to slip out of position and to fall off the flange due to thermal contraction or the like.